Portable, Hand-Held Inspection System for Aircraft Components

New technology is needed for the nondestructive detection and characterization of defects in aerospace structures, particularly those with complex shapes, that are used in high stress environments that accelerate degradation. Existing nondestructiveevaluation (NDE) techniques, based on ultrasonics, eddy-currents, and x-radiography do not have the capabilities needed for real-time defect detection and imaging using highly portable instrumentation. RMD proposes an NDE instrument based on an array of magnetoresistive (MR) sensor elements used to produce real-time images of induced magnetic fields within tubular structures. Recent advances indicate that both linear and 2-D MR sensor arrays can befabricated with sensor dimensions less than 1 mil. A sensor array containing minute sensor elements could provide high spatial resolution images of induced magnetic fields that are perturbed by small defects. Correlating the magnetic field properties atmany points, with the positions where the measurements are made, allows the generation of real-time, 3-D images of defects. The sensitivity of a coil is limited to approximately 2.50 x 10-4 T/?Hz while MR sensors have achieved sensitivity of approximately 1.0 x 10-11 T/?Hz. MR sensors have bandwidth greater than 1 GHz, they can withstand forces of 100,000g, and temperaturesover 2000C.The PI and his collaborators have been able to develop MR sensor systems for recovering data on obsolete or damaged magnetic tapes, and for detecting cracks and corrosion in sheet metal. Recent advances in sensor design and addressing suggest that alinear array for imaging defects in metals should now be feasible. The new inspection and imaging technology will find a number of markets in nondestructive evaluation (NDE) including the aircraft, electronics, automotive, chemical, and power industries. It will be give inspectors a major new technology for ensuringthe condition and safety of aircraft, pipelines, transportation vehicles, and power plants.